Michael Carneal - AP 2011
FILE - Michael Carneal, 27, is escorted by a guard from the U.S. District Courthouse in Paducah, Ky., March 18, 2011. Carneal pleaded guilty in 1998 to killing three students and injuring five others in 1997 at Heath High School, when he was 14.  (Stephen Lance Dennee/The Paducah Sun via AP, File)